Towards Field Theory in Spaces with Multivolume Junctions

TL;DR

This paper develops a theoretical framework for understanding wave propagation and junction conditions in multivolume spacetime models, with applications to quantum cosmology, braneworlds, and string theory.

Contribution

It introduces junction conditions for various spin fields in multivolume spacetimes and explores their implications in quantum universe creation and string theory contexts.

Findings

Derived universal wave propagation laws across junctions.

Established junction conditions for fields of different spins.

Applied the theory to models of quantum universe creation.

Abstract

We consider a spacetime formed by several pieces having common timelike boundary which plays the role of a junction between them. We establish junction conditions for fields of various spin and derive the resulting laws of wave propagation through the junction, which turn out to be quite similar for fields of all spins. As an application, we consider the case of multivolume junctions in four-dimensional spacetime that may arise in the context of the theory of quantum creation of a closed universe on the background of a big mother universe. The theory developed can also be applied to braneworld models and to the superstring theory.